Parkinson's Disease: Advances in Treatment and the Syntheses of Various Classes of Pharmaceutical Drug Substances

An overview of Parkinson's disease (PD) prevalence, diagnosis, and currently available treatment options is provided. A comprehensive list of different classes of marketed pharmaceutical drug products and the syntheses of various drug substances are summarized based on published literature.

Recent Advances in the Synthesis of Xanthines: A Short Review

Xanthine and its derivatives are considered a pharmacologically potential moiety that manifests immense biological activities. Owing to this much diversity in the biological field, this scaffold has fascinated the attention of many researchers around the globe to scrutinize its basic structure chemically as well as biologically. In recent years, xanthine derivatives have been used therapeutically in different pathological conditions due to their presence in day-to-day life. Herein, we review the recent progress in the synthesis of xanthine and its derivatives. Some of the widely used synthetic strategies such as (a) Traube's synthesis, (b) one-pot synthesis, (c) xanthine-anneleated synthesis, and (d) miscellaneous synthesis were compiled in this review paper. The results obtained from this review paper highlight the significance of various xanthine derivatives as possible leads to the development of new drugs. The data compiled in this review paper could help the medicinal chemist in designing new active compounds from the modification of the already existing compounds in the search for novel drug leads. This report concludes that the various synthetic procedures exemplified in this review paper may serve as a support system for the designing of new molecules with a xanthine scaffold. Thus, we hope that this molecule may serve as the prototype in order to find out more active xanthine derivatives.

Microwave-assisted reactions: Efficient and versatile one-step synthesis of 8-substituted xanthines and substituted pyrimidopteridine-2,4,6,8-tetraones under controlled microwave heating

We report herein a simple and efficient one-step synthesis of 8-substituted xanthines and substituted pyrimidopteridine-2,4,6,8-tetraones via reaction of 1,3-dimethyl-5,6-diaminouracil 1 with activated double bond systems 2 assisted by controlled microwave irradiation. The obtained heterocycles are privileged biologically relevant scaffolds.

Solid-Phase Synthesis of 1,3,7,8-Tetrasubstituted Xanthine Derivatives on Traceless Solid Support

Traceless solid-phase synthesis of 1,3,7,8-tetrasubstituted xanthine (1,3,7,8-tetrasubstituted 1H-purine-2,6(3H,7H)-dione) derivatives has been developed. The solid-phase synthetic route began on a solid supported N'-cyano-N-substituted carbamimidothioate, which was prepared from cyanamide, isothiocyanate, and Merrifield resin. After N-alkylation of carbamimidothioate resin with ethyl 2-bromoacetate, an imidazole ring is introduced by Thorpe-Ziegler-type cyclization. The resulting imidazole resin is converted to 1,3,7-trisubstituted xanthine resin using sequential reactions, such as Lewis acid-catalyzed urea formation, pyrimidine ring cyclization, and N-alkylation. After oxidation of sulfides to sulfones, traceless cleavage with amine or thiol nucleophiles afforded the desired 1,3,7,8-tetrasubstituted xanthines in good purities and overall yields (eight-steps; 36 examples). This efficient solid-phase synthesis enables the incorporation of four diversity points into the preparation of the 1,3,7,8-tetrasubstituted xanthines.

Design and evaluation of xanthine based adenosine receptor antagonists: potential hypoxia targeted immunotherapies

Molecular modeling techniques were applied to the design, synthesis and optimization of a new series of xanthine based adenosine A(2A) receptor antagonists. The optimized lead compound was converted to a PEG derivative and a functional in vitro bioassay used to confirm efficacy. Additionally, the PEGylated version showed enhanced aqueous solubility and was inert to photoisomerization, a known limitation of existing antagonists of this class.